Communicable diseases

• What are communicable diseases caused by?

  Pathogens that can spread between organisms
• How do communicable diseases differ from non-communicable diseases?

  Communicable diseases are infectious, non-communicable are not
• What are the four main types of pathogens?

  • Bacteria
  • Viruses
  • Fungi
  • Protists
• What type of cells are bacteria?

  Prokaryotic cells without a nucleus
• How do bacteria reproduce?

  By binary fission rapidly
• What do bacteria release that causes illness?

  Toxins that damage tissues
• What are viruses smaller than?

  Bacteria
• How do viruses replicate?

  By invading host cells and using their machinery
• What happens to host cells when viruses burst out?

  They are destroyed
• What virus affects plants and discolors leaves?

  Tobacco Mosaic Virus
• What are fungi made of?

  Hyphae or single-celled structures
• How do hyphae affect human skin or plant surfaces?

  They can penetrate and spread spores
• What type of cells are protists?

  Single-celled eukaryotes
• How do some protists cause damage?

  By living inside a host as parasites
• How are protists often spread?

  By vectors
• What protist causes malaria?

  Plasmodium
• How do pathogens spread through direct contact?

  Through touch or bodily fluids
• What disease is spread through contaminated drinking water?

  Cholera
• How do airborne pathogens spread?

  Through droplets from sneezing or coughing
• What disease is spread through contaminated food?

  Salmonella
• How is malaria transmitted?

  By mosquito bites
• What are the modes of transmission for pathogens?

  • Direct Contact
  • Water
  • Airborne
  • Food
  • Vector Transmission
• What are the non-specific defences of the human body?

  • Skin: Barrier and antimicrobial secretions
  • Nose Hairs & Mucus: Trap pathogens
  • Cilia & Mucus: Sweep out bacteria
  • Stomach Acid: Kills pathogens
• What is the function of skin in the body's defence system?

  Acts as a barrier and produces antimicrobial secretions
• How do nose hairs and mucus protect the body?

  They trap pathogens before entering the respiratory system
• What do cilia and mucus in the trachea do?

  They sweep mucus and trap bacteria out
• What is the role of stomach acid in the body's defence?

  Kills pathogens before they reach intestines
• What are the roles of white blood cells in the immune system?

  1. Phagocytosis: Engulf and digest pathogens
  2. Antibody Production: Recognize and destroy pathogens
  3. Antitoxin Production: Neutralize bacterial toxins
• How do vaccines work?

  Inject dead or inactive pathogens to stimulate immunity
• What do white blood cells produce after vaccination?

  Antibodies
• What do memory cells do after vaccination?

  Respond quickly if infected later
• What are the key points regarding communicable diseases?

  • Caused by bacteria, viruses, fungi, protists
  • Spread through various transmission modes
  • Body defences include skin, mucus, and WBCs
  • Vaccination protects individuals and communities
  • Antibiotics work against bacteria, not viruses
  • Hygiene and vector control prevent infections
• What are the symptoms of HIV/AIDS?

  Flu-like symptoms and immune failure
• How is HIV transmitted?

  Through direct contact with sexual fluids or blood
• What is the prevention method for HIV/AIDS?

  Condoms and antiretroviral drugs
• What are the symptoms of measles?

  Fever and red rash
• How is measles transmitted?

  Through airborne droplets from coughs or sneezes
• What is the prevention method for measles?

  MMR vaccine
• What are the symptoms of salmonella infection?

  Vomiting and diarrhoea
• How is salmonella transmitted?

  Through contaminated poultry or eggs